Field of the Invention
This invention generally relates to indicator devices and more specifically to an indicator device for installation with a stove burner control shaft for announcing the status of a corresponding burner.
Description of Related Art
Many modern gas and electric stoves contain an integral visual indicator, such as a status light, for displaying the status of each burner. Basically, when a burner is off the visual indicator is off. When the burner is on, the visual indicator produces a readily visible light output. However, many stoves currently in use do not include such integral visual indicators. The ability to retrofit an existing stove with an economical device that provides a visual indication of burner status would be useful particularly if the retrofit were available to a consumer at an economical price and were easy to install and use.
U.S. Pat. No. 6,733,146 (2004) to Vastano discloses an Illuminated Knob for Indicating the Operative Condition of an Appliance. In one embodiment retrofitting existing stoves is accomplished by replacing an existing burner control knob on a control shaft with an entirely new burner control knob that provides illumination as an indication of burner status. This burner control knob has front and rear surfaces and an outer edge that defines an internal battery compartment accessible from the front of the knob. The burner control knob carries a battery, a light emitting diode (LED) that extends radially to the exterior of the knob and an attitude sensing switch. When the burner control knob is in an “off” position, the attitude sensing switch is open and the LED is off Upon rotation of the burner control knob from the off position to any other angular position, the attitude sensing switch closes to energize the LED and produce light.
Although Vastano's device provides a visual indication of burner status, it is integral with a burner control knob and replaces the original burner control knob. Moreover, the operation of Vastano's sensing switch is dependent upon gravity. Conductivity through the switch exists only through about 180° of rotation at which point the conductive material will not contact both sets of switches. Typically, however, a burner control knob and the control shaft rotate through a larger range (e.g., 270°). Also, with this type of switch the burner control shaft must be horizontal to assure that in a reference position and that the conductive material is not in contact with switch terminals when the switch is in the “off” position. The cost of the Vastano's device includes the cost of a support element for an indicating apparatus and an element to provide the tactile function of the original burner control knob. Access to the battery compartment for battery replacement in this replacement burner control knob requires a front element to be removed. The manufacture of such a removable element increases the device complexity and, consequently, its manufacturing cost. In addition, it may be necessary for this implementation to be made in several models to accommodate different stove configurations in the vicinity of the burner control knobs and to accommodate different burner control shaft diameters.
U.S. Pat. No. 7,816,818 to Sellecchia (2010) discloses a Stove Knob Timer Device which includes a main housing for engaging a stove operational or control shaft. When the control shaft rotates to activate a respective stove burner, the timer is actuated. After a predetermined time an annunciator comprising a speaker is activated to prompt a user to monitor the stove and to press a reset button to deactivate the speaker. Failure to press the reset button in a timely manner causes the timer device to emit a more aggressive alarm. When the reset button is pressed, the timer is reset so the burner continues to be energized although the annunciator is silent until the timer interval expires. Sellecchia's device contains many mechanically complex mechanism components that will be expensive to manufacture.
What is needed is a device that provides a visual indication, an audible indication or both of burner status that is adapted for installation on stoves during manufacture and for retrofitting existing stoves, that is adapted for application with burner control shafts extending along horizontal, vertical or intermediate axes, that is economical, that is easy to install on original equipment and as a retrofit, that is easy to use and that can be adapted for use in a variety of different stove configurations.